Electrostatic chucks are often used to clamp substrates to substrate supports during horizontal substrate processing. Conversely, substrates processed in a vertical orientation are often held on a substrate carrier using a mechanical clamping force. Conventional mechanical clamping carriers used to hold a substrate during transfer and processing may often have poor positional accuracy and may also generate particulate during chucking due to the high mechanical clamping force.
In OLED fabrication, positional accuracy of the mask used over the substrate during deposition of OLED materials is challenging, particularly as the size of the substrate increases. Traditional conventional mechanical clamping carriers which generally hold the edges of the substrate at may contribute to poor positioning of the mask over the substrate since the clamping force is difficult to uniformly apply to the substrate, which may cause the mask to bow or shift position.
Therefore, a need exists for an improved apparatus and method for clamping substrates and masks during vertical and horizontal substrate processing.